The early neonatal period is the time of greatest animal loss for pork producers. The 1991 USDA National Swine Survey on Morbidity/Mortality and Heath Management of Swine in the U.S. estimated that overall pre-weaning mortality was 15% and that nearly all cases of morbidity and mortality occurred in piglets less than 7 days of age (USDA, 1991). Importantly, 58% of the cases of morbidity were reportedly due to scours and 30% of the mortality was attributed to scours or starvation.
In recent years, pork producers have reduced lactation lengths in an attempt to maximize the number of piglets born per sow per year. Lactation periods of 10–14 days are common in the swine industry. This production system creates a need for sows that produce high levels of milk in early lactation in order to obtain maximal piglet growth. In addition, the number of piglets born per litter has increased, thus adding to the demand for higher milk production early in lactation.
Low milk production is manifested by slow piglet growth before weaning and suboptimal growth post-weaning (Hartman et al., Symp. Zool. Sci., 51:301 [1984]). Milk production accounts for 44% of the growth weight of the piglets (Lewis et al., J. Anim. Sci., 47:634 [1978]). In addition, gastrointestinal disease in piglets reduces their survival. Such diseases are typically treated with antibiotics. It has also been suggested that bioactive substances in milk may have important functions in piglet growth and health.
Clearly, the industry would benefit from a method of increasing milk production and nutrient value in sow milk. Supplementing milk with growth factors or nutrients is too costly and labor-intensive to be a viable solution. The art is in need of a cost effective method of increasing milk production and nutrient value in lactating sows.